thomson



(No Model.) 2 Sheets-Sheet L E. THOMSON. BLEGTRIG LAMP.

No. 283,437. PatentedAug. 21, 1883.

l (No Model.) 2 Sheet-Sheet 2.

E. THOMSON.

ELECTRIC LAMP. I No. 283,437. Patented Aug. 21, 1883.

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UNITED STATES PATENT OFFICE.

ELII-III THOMSON, OF NEWV BRITAIN, CONNECTICUT, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF SAME PLACE.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 283,437, dated August21, 18 83.

' A Application filed March 2,1881. (No model.)

To all whom it may concern Be it known that I, EL'IHU THoMsoN, a citizenof the United States, residing at New Britain, in the county of Hartfordand State of Connecticut, have invented certain new and usefulImprovements in Electric Lamps; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, and to theletters or figures of reference -marked thereon, which form a part ofthis specification. 7

My invention relates to improved means of regulating the distance of twocarbon pencils apart, when used for producing an arc, and in adaptingsaid distance or arc length to va-g rious changes in the circuit inwhich the arc is operated, and in promoting steadiness of light andconstancy of operation.

My invention further consists in a novel combination of devices foreffecting a feed, consisting of a derived-circuit magnet, an electro-magnetucontrolling, in any suitable man ner, the feed mechanism ofthe lamp, and an adjustable resistance controlled or varied by thederived-circuit magnet, in any suitable manner, so as to vary the amountof current flowing in the feed-regulating magnet, in the manner to behereinafter described.

Figure 1 is a front view of the mechanism of a lamp embodying myimprovements; Fig. 2, a side view of the same, only those parts shownwhich are described in connection with Fig. 2; Fig. 3, a detailed viewof a self-locking clutch or toe engaging with a disk, WV; Fig. 4, an endview of the shunt-magnet and the variable-contact device to be operatedthereby, as hereinafter described; Fig. 4, a top view of the same. Figs.5 and 6 show modes of constructing a variable contact or cut-out for theliftingmagnet, operated by the shuntmagnet K.

In Fig. 1, R is a'carbon rod, supporting the upper electrode or carbonpencil, E, and racked or otherwise connected, so that in moving downwarda rotary motion is given to the disk W, mounted upon a shaft upheld bysuitable supports. Centering upon this shaft is a frame, F, serving as asupport and guide for a selflocking clutch mechanism, T,

which engages upon the edge of the disk IV, I

as shown. The magnet-core M and coil C are so arranged as to impart amotion to the frame F and toe or clutch T, so as to lift the carbon rodwhen the current is flowing. A spring, S, may cause a return of saidframe F and toe T when the current ceases to pass through the coil 0. Ashuntanagnet, K, in a derived circuit, 5, around the arc, attracts itsarmature A against the action of a spring, S, and in so attracting itsarmature closes a set of contacts, 1) g, which constitute a variablecut-out or short circuit around the lifting-magnet coil 0, as shown Thecurrent enters the lamp, pass ing through the coil C, thence to theupper carbon, E, to the lower carbon, E, and out through the framesupporting the lower carbon and suitable connections, which areinsulated from the body of the lamp, part being diverted through theshunt-magnet K, for the control of the cutout p q. These generaloircuits are shown in Fig. 1. Upon the shaft of the wheel WV, Isometimes place a thread of considerable pit-ch, V, Fig. 2, and in saidthread a projection from one extremity of a lever J, engages, while theother extremity of lever is attached to the piston of a dash pot, Thedasl1pot D thus operates to prevent too rapid rotation of the screw Vand wheel IV, since any ch, nge in the position of said screw or wheelwill necessitate a change in the relation of the piston in its cylinderD.

Fig. 3 shows the preferred construction of the clutching device T. Itconsists of a hinged toe striking the wheel W, slightly above alinejoining the centers of the wheel and pivot of said toe T, as shown. Thetoe T is borne upon the frame F, as aforesaid, and is held in placeagainst the wheel IV by a light spring, Z, or its own weight may besufficient for this purpose. A projection or pillar, H, fixed to theframe of the lamp, is placed so that upon the descent of the toe T andframe F it lifts said toe and releases the wheel IV, and the carbon rodmoving therewith.

Fig. 4 shows the manner of securing a variable contact, or a contactwhose power to divert current from the magnet-coil C is greater as thepower of the shunt-magnet is greater. The magnet K, placed in a shuntaround the arc, as aforesaid, in attracting its armature A, brings eachof a series of contacts, 1), borne by said armature into successiveconnection with a similar fixed series. The pieces of the fixed seriesare joined electrically by a series of fine wire loops, R, orresistances, and are otherwise insulated from one another. Each of thecontacts upon the armature is attached thereto by a light spring, so asnot to interfere with the free movement of the parts as the contacts aresuccessively made. \Vhen the armature A is attracted to its magnet K,the contacts are closed successively, so as to interpose less and lessof the resisting-loops R in the circuit of the contacts, until finally acomplete cut-out or contact of no resistance is formed by the closing ofthe last pair of contact-points.

It will now be convenient to describe the action of the lamp as thusconstituted.

\Vhen the current flows through the coil 0, Fig. 1, the core M isattracted and lifts the frame F, closing the clutch or toe T upon thedisk XV, which is thereby rotated so as to lift the rod R, and soestablish the are between the electrodes E E. The separation thus madeis retained until by the consumption of the electrodes, the resistanceof the are being increased, a greater portion of the current is diverted.through the shunt-magnet K, which now attracts its armature A, closingsome of the contact-points at p q, thereby diverting a portion of thecurrent from the magnet-coil C. A weakening of the attraction of thecoil 0 upon its armature-core M results in a partial release of theframe F, and consequent approach of the electrode E to E takes place. Bycon: tinued consumption of the electrodes and further contacting at p q,the magnet-coil O is so far out out that the toe T, coming in contactwith the pillar H, Fig. 3, is opened, and the,

- wheel or disk \V is free to move and rod 11'. free to descend. Thetoo'sudden descent is checked by the screw V, lever J, and dash-pot D,acting in conjunction, as before described.

It is preferable that during action of the lamp a partial. cut out orpartial contacting at p (1 shall at all times exist, and that the effectof said cut-out contacts upon the power of the magnet-coil 0 shall bedue to its variations of resistance only.

Fig. 5 shows a modification of the variable cut-out shown in Fig. 4.. Cis the lifting-magnet coil; K, the shunt-magnet. The lever A, bearingthe shunt-armature, is provided with an arc of metal resting upon astrained wire, it, of high resistance, attached to a support, G, asshown at 1?. By the gradual attraction of thcarmature A the point ofcontact upon R is shifted so that it is made practically of shorter andshorter length, and the short cir cuit around 0 more complete.

Fig. 6 shows a modification in which the wire it, of high resistance, ismoved by the armature A of the shunt-magnet K so as to contact upon ametal surface, 1 at successive points, and thus provide avariable-resistancc contact.

Other adjustable resistance devices controlled by the derived-circuitelectro-magnet may be used in place of the one described, for

the purpose of producing the varying slumtto the regulatingelectro-magnet,without departing from the spirit of my invention. Onesuch device is shown in prior application filed by me December 17, 1880,and consists of a slit spring or comb whose teeth are arranged to makecontact successively with a carbon or other resistancesurface, theamount ot'resistance depending upon the number of teeth that aresinmltaneously in contact with said surface.

What I claim as my invention is- 1. The combination, with the brake orfriction disk WV, geared to the carbon-carrier, of

thespring or equivalently actuated pivoted friction toe or clutchnormally bearing against the outer periphery of the disk, at fixed stoparranged in the path of the friction toe or clutch and mounted on afixed portion of the frame, and a support for said pivoted clutchconnected with the regulating-magnet.

2. The combination, substantially as described, of a controllingelectro-magnet in a derived circuit, an electro magnet in the maincircuit for operating the regulating devices, a high-resistance wireforming a pen tion of a derived circuit around the latterelectro-magnet, and contact surfaces and points governed by thecontrolling electro-magnet, whereby more or less ofthelength of saidhighresistance wire may be interposed in the derived circuit around themain circuit or regulating elcctromagnet, substantially as described.

3. In an electric lamp, a control]ingtrain,

a screw, V, and lever J, in combination with a dash-pot, D, asdescribed.

l. The combination, in an electric lamp, of

a feed-controlling coil or electro-magnet, a va riable or adjustableresistance in a branch circuit around the same for varying the saidmagnets power, and a derivcd-cirmlit magnet or c0il.in a derived circuitaround the are, controlling said resistance.

5. The combination, in an electric lamp, of

- a feed-regulating magnet, a variable resistance controlling the llowof current in the coils of such magnet, so as by its variations to varythe power thereof, and suitable means inde pendent of said magnet forautomatically operating said resistance in accordance with changes inthe length of are, whereby the feed of the carbon may be governed.

6. The combination, in. an electric lamp, of a main or principal magnet,a variable resistance in a branch around coils of said magnet, forcontrolling the flow of current in said coils, and thereby varying thepower of the magnet, and means for varying said resistance in accordance with changes in. the length of are.

In testimony whereof I affix my signature in presence of two witnesses.

ELIHU 'lHOMSON.

Witnesses:

G. 1V. Hana, E. XV. Bron.

